Miniature light structure



June 17, G. A. CURL MINIATURE LIGHT STRUCTURE Filed Sept. 21, 1966 F G. /NVENTO Q. l 2 GERALD A. CURL f'ozta padl'u'gw Arrow/Em June 17, 1969 G. A. CURL 3,450,870

MINIATURE LIGHT STRUCTURE Filed Sept. 21, 1966 Sheet 2 of 2 INVENTOR GERALD A. CURL United States Patent 3,450,870 MINIATURE IGI-IT STRUCTURE Gerald A. Curl, Van Nuys, Calif., assignor to Coastal Dynamics Corporation, a corporation of California Filed Sept. 21, 1966, Ser. No. 581,011 Int. Cl. B60q 3/04 U.S. Cl. 240-816 9 Claims ABSTRACT OF THE DISCLOSURE This invention relates generally to miniaturized light structures and more particularly, to improved miniature light sources for panel structures, such as edge lighted panels.

Edge lighting of panels is well known in the art and has wide applicability, particularly in the illumination of instrument, control, and console panels in aircraft. In such panels, light is usually transmitted through the edge of a plastic or light conducting core material. This material is provided with an opaque surface coating except for transparent areas in the shape of letter or numeral characters through which light is emitted. The letter or numeral characters form the nomenclature identifying the control positions of the switches, instruments, and other devices assembled on the panel.

A desirable feature in edge lighted panels of the foregoing type is to provide proper light sources and connections thereto distributed in the panel in a manner which avoids projections through the panel surfaces. In other words, a flush surface is desirable not only to facilitate mounting the panel but to avoid interference with other instruments which are inserted through the rear of the panel. In some panels heretofore provided wherein a flush surface is realized, it has been necessary to pot the entire lamp structures directly into the panel itself. A printed type circuit may then be used to energize the various lights within the panel and thus avoid any appreciable projections from the rear surface. However, if a bulb or lamp should burn out, it is an expensive and time consuming operation to replace the lamp, such operation generally requiring destroying part of the panel structure itself as well as the printed circuit connections to the lamp. As a consequence, many more lamps than actually necessary for proper lighting in such type panels have been required simply to meet defined safety standards.

It will be evident that if a lamp structure could be designed for easy removal and replacement without having to appreciably disturb the remaining portions of the panel, lights could be immediately replaced that are burnt out and thus the overall number of lights presently required for safety purposes would not be necessary all to the end that greater economy and ease of manufacture would be realized.

Some panels have been designed with the foregoing considerations in mind wherein the lamp may be replaced without disturbing the actual power connections to-a suitable socket structure incorporated in the panel. However, the available designs usually result in a projection of a portion of the lamp or socket structure above 3,450,870 Patented June 17, 1969 'ice either or both the top and bottom surfaces of the panel.

Further problems with respect to edge lighted panel structures heretofore available relate to the actual wiring connections for energizing the lamps themselves, Usually when the lamp is incorporated directly in the panel in a manner to avoid projections, some of the connecting leads pass in front of a portion of the lamp itself. While the light eclipsed may not be appreciable, it cuts down generally on the entire illumination of the panel and it would be preferable to provide a lamp structure wherein light is radiated from the lamp through the plane of the panel omni-directionally or over 360".

. Another extremely important consideration with respect to edge lighted panels, particularly in a structure enabling easy removal and replacement of one of the lights, involves the assurance of proper electrical contact after a light bulb has been removed and replaced. The extreme miniaturization of the light source, which is necessary to avoid increasing the bulk and size of panels appreciably, and also necessary to avoid interference with control switches and instruments on the panel, increases the risk of failure of contact particularly when a bulb is simply threaded into a socket. Unless complete threading takes place, a contact may not be effected. Also, vibrations may possibly result in a partial unthreading of a lamp structure from its socket and thus break a contact.

Other considerations relate to the avoidance of hot spots, halo effects from miniature lights employed in edge lighted panels, and the provision of a panel design for effecting connections to the light sources which facilitates assembly operations.

With the above in mind, it is a primary object of the present invention to provide a greatly improved miniature lamp structure particularly suitable for edge lighted panels in which the desirable features as outlined above are realized.

More particularly, it is an object to provide a miniature light structure in combination with an edge-lighted panel with no projections from the panel surfaces as a consequence of connections or the like to the lamps being evident and yet wherein a lamp may be very easily removed and replaced should it burn out without in any way disturbing the circuit connections within the panel.

Another important object is to provide a unique miniature light structuredesigned for incorporation in an edge lighted panel wherein, in one embodiment, light emission from the lamp over 360 in the plane of the panel is realized, there being no eclipsing of any portion of the light as a consequence of wire connections or electrodes.

Another object is to provide a unique panel and miniature light structure design such that installation of the miniature light assembly in the panel is greatly facilitated.

Another important object is to provide a miniature light assembly designed such that the lamp may be easily removed and replaced and yet incorporating novel electrical contact configurations assuring that electrical continuity will be maintained even if the lamp structure should work partially loose in its mounting within the panel all to the end that greater reliability and safety are assured.

Aonther object is to provide a combination miniature light structure and edge lighted panel so designed that the panel may easily be modified so that removal and replacement of the lamps may be effected from the top surface. In this respect, the panels are preferably designed so that the top surfaces are completely clear of any structures associated with the illuminating lamps and their connections. For this to be realized the replacement of lamps is preferably effected from the bottom of the panel. How ever, there are instances in which it is desirable to enable easy replacement from the top surface of the panel even though the small area involved eliminates part of the space that could be used for legends and the like.

Briefly, these and many other objects and advantages of this invention are attained by provided a miniature light structure in the form of two basic units. First, there is provided a filter assembly including a lamp housing and electrical lead means extending laterally from the lamp housing. This assembly is arranged to be permanently installed in a suitable bore structure formed in the bottom surface of an edge lighted panel when the miniature light structure is to be used for this particular application. The second basic unit comprises a cap and lamp assembly including contacting means for cooperation with the electrical lead means in the filter assembly. The design is such that the cap and light assembly may be received in the lamp housing in such a manner that proper electrical connection is effected between the contacting means and the electrical lead means within the lamp housing.

When used in combination with an edge lighted panel, the bottom surface of the panel, in addition to a receiving bore, includes routed out conductor channels for carrying powder leads, at least two of these channels passing adjacent diameteric opposite wall portions of the bore and including small electrical lead channels intercepting the bore for receiving the electrical lead means extending laterally from the filter assembly. The electrical leads are electrically connected to the power conductors in the channels at the cross over points. It is then a simple matter to fill in the channels with a suitable resin and at the time of final assembly, thread in the cap and lamp assemblies. The design is such that after the cap and lamp assemblies have been fully received in the filter assemblies within the panel bores, the bottom surface of the cap and lamp assemblies are flush with the bottom surface of the panel.

A better understanding of the invention as well as various further features and advantages thereof will be had by now referring to preferred embodiments as illustrated in the accompanying drawings, in which:

FIGURE 1 is a fragmentary perspective view illustrating the top surface of an edge lighted panel incorporating the miniature light structures of this invention;

FIGURE 2 is a fragmentary exploded perspective view of a bottom portion of the panel during a manufacturing step in assembling one of the miniature light structures in the panel;

FIGURE 3 is an exploded perspective view of various components making up a cap and lamp assembly unit constituting one basic part of the miniature light structure;

FIGURE 4 is a fragmentary cross section of one of the miniature light structures as incorporated in the panel of FIGURE 1 taken generally in the direction of the arrows 4-4 but illustrating the cap and lamp assembly unit only partially inserted in the remaining structure; and

FIGURE 5 is another view partly in cross section of a modification of the combination edge lighted panel and miniature light structure for providing access to the light from the top surface of the panel.

Referring first to FIGURE 1 there is illustrated an edge lighted panel including a light conducting core preferably in the form of a flat sheet of acrylic material having the property of conducting light. The upper surface of the core 10 is first covered with a translucent white substance such as a paint 11 and thereafter with an opaque coating 12. Suitable letters or numeral characters 13 forming desired nomenclature are defined by omitting portions of the opaque coating 12 or removing given portions in the shape of the desired legend to expose the white translucent underpaint.

Distributed throughout the panel are a plurality of light sources for generating light which is transmitted by the light conducting properties of the panel core 10 to illuminate the legends 13. Two of these light sources are located within suitable bores such as indicated in dotted lines at 14 and 15 extending normally into the panel from its bottom surface. The under surface of the panel also includes suitable channels such as indicated by the dotted lines 16 and 17 which pass adjacent opposite portions of the bores 14 and 15. These chanels serve to carry power conductors 18 and 19 for energizing the light structures incorporated in the bores.

The foregoing arrangement will become clearer by referring to FIGURE 2 wherein there is illustrated in detail the bore 14 prior to assembly of the light structure within the bore.

In FIGURE 2 it will be noted that in addition to the bore and channels there are provided small lead channels 20 and 21 extending laterally from the Walls of the bore 14 and intercepting the channels '16 and 17 respectively. The various channels involved may readily be formed on the underside of the panel core -10 by a suitable routing operation.

Shown exploded below the bottom surface of the panel is the miniature light structure of the present invention. This structure is made up of two basic units. The first unit is indicated generally at 22 and constitutes a filter assembly comprising a lamp housing 23 including an opaque coating 24 surrounding an internally threaded base ring 25. The threaded base ring 25 defines a lower opening to the lamp housing 23. A first electrical lead means 26 extends laterally from one side of the lamp housing and is in electrical engagement with the base ring 25. A second electrical lead means includes a central contact portion preferably in the form of a ring 27 in the lower opening within the base ring 25 and a laterally extending portion 28. The extending portions of the respective leads are arranged to be received within the lead channels 20 and 21 when the lamp housing is inserted in the bore 14 as will be clear from the exploded orientation in FIG- UR-E 2.

After the filter assembly has been inserted in the bore 14 so that the extending lead portions 26 and 28 are received in the channels 20 and 21, the power conductors 18 and 19 are positioned in the channels 16 and 17 respectively to overlie the electrical leads. Suitable soldered or other type electrical connection can then be effected between the respective power conductors and the leads at the points of cross-over.

The second basic unit of the miniature light structure constitutes a cap and lamp assembly designated generally by the numeral 29 shown exploded below the filter assembly 22. This cap and lamp assembly includes a cap 30 which is externally threaded as shown and includes a small screwdriver slot 31 in its bottom surface. A suitable lamp 32 in turn is supported by the cap structure.

Further details of this cap and lamp assembly are illustrated in FIGURE 3. As shown, this assembly includes a disc shaped insulating washer 33 arranged to be received within the cap 30. Above the washer type insulator 33 is a center contact 34 in the form of an annular collar member of conducting material. Suitable insulating means also annular in form as indicated at 35 in turn is arranged to be received over the collar to lie between the exterior annular wall of the collar 34 and the inner wall of the cap 30. The assembly is completed by the lamp 32 which includes input wire leads 36 and 37 bent to extend straight downwardly and laterally, respectively.

When the foregoing structure is assembled, the straight down extending wire lead 36 will pass through the insulator 35, collar 34 and a small opening 38 formed in the insulating washer 33 to engage the cap 30 and thus effect an electrical connection to the cap 30. The laterally extending wire 37, on the other hand, electrically connects to the conducting collar member 34. The insulating means 35 holds the assembly together as a complete unit.

Referring now to FIGURE 4, the miniature light structure is illustrated in its assembled relationship incorporated in the panel 10. Thus, it will be clear that the laterally extending electrical lead means 26 and 28 are in electrical engagement with the power conductors 18 and 19 passing through the channels 16 and 17 respectively. Further, it will be evident that as the cap 30 is threaded into the lower opening defined by the threaded base ring 25 for the lamp housing, the wire 36 from the lamp 32 will be in electrical engagement with the lateral extending lead 26 through the cap 30 and base ring 25. Preferably, this constitutes the grounded side of the circuit.

The other lead 37 from the bulb 32 is shown connected to the collar member 34 at the lower portion thereof and the annular insulating means 35 is illustrated in position. It will be noted that there is provided a small annular ridge on the insulating means 35 and a corresponding annular groove on the inside of the cap 30. This arrangement locks the insulation in place and will hold the collar member 34 in concentric relationship as well as secure the washer 33 in the lower portion of the cap 30.

As threading of the cap 30 continues, it will be clear that the collar member 34 will engage the center contact portion 27 for the laterally extending electrical lead 28. As described in FIGURE 2, this center contact portion is preferably in the form of a ring of diameter corresponding substantially to the diameter of the collar 34 so that there will be an engagement of the upper annular edge of the collar with the ring.

In accord with an important feature of this invention, it will be noted that this center contact ring portion 27 is flexed downwardly slightly as viewed in FIGURE 4. By so bending the center contact 27, it will be engaged by the collar member 34 prior to complete threading of the cap 30 within the base ring 25. As the threading continues to move the cap member 30 upwardly in the direction of the arrows of FIGURE 4, the collar member 34 will flex the center contact 27 upwardly against the underside of the lamp housing so that it will assume a position substantially coaxial or concentric with the collar and there will be complete 360 engagement of the top edge of the collar 34 with ring contact 27. With the cap 30 completely threaded into the base ring 25, the center contact 27 will always be exerting a downward bias force against the collar 34 so that any slight unthreading that may occur will not result in any electrical disconnection of the center contact with the collar. This feature is important from a safety standpoint in that any vibrations or the like which might work the cap 30 loose to effect a partial unthreading thereof will not result in a loss of contact. However, it should be noted that a further additional advantage of the spring bias exerted by the center contact 27, is that the bias force tends to effect a thread look so that unintentional unthreading of the cap 30 from the base ring 25 is extremely unlikely.

It will be noted in FIGURE 4 that part of the top surface of the lamp enclosure 23 is defined by a metallic member 39. This metallic member serves as a heat sink and in addition will block light from the lamp from passing directly through the top of the bore and thus avoid hot spots and also avoid halo effects.

It will be appreciated from the assembly relationship illustrated in FIGURE 4 that light from the lamp 32 will pass through the lamp housing 23 over 360 in the plane of the panel core there being no obstruction ofany portion of the light by the electrically extending leads 26 and 28 or other components of the unit. Preferably, the lamp housing is made up of a special type of plastic filter which serves to diffuse the light in a desired manner in view of the filament geometry so that there is substantially equal illumination over the 360 in the plane of the panel.

It will also be clear from FIGURE 4 that it is an extremely simple matter to remove and replace the cap and lamp assembly in the event a bulb should burn out. In this respect, it should be noted that such removal and replacement can be effected without in any manner disturbing the connections of the filter assembly leads 26 and 28 to the power conductors 18 and .19 and in fact the panel itself is in no way disturbed. Finally, it will be clear that when the cap 30 has been completely threaded within the base ring 25, the bottom surface of the structure is flush with the bottom surface of the panel.

Referring now to FIGURE 5, there is shown a means for modifying an edge lighted panel so that the cap and lamp assembly may be inserted or removed from the top surface of the panel without necessitating a major modification in the miniature light structure itself. Thus, in FIGURE 5 there is shown a fragmentary portion of a panel core 40 provided with a bore 41 similar to the bore 14 of FIGURE 4 and suitable conductor channels 42 and 43 for carrying conductors 44 and 45 all in the same manner as described in FIGURE 4. However, in the embodiment of FIGURE 5 there is provided a counter-bore 46 of larger diameter than the bore 41 formed to inter cept the bore 41 as illustrated at the top of the panel. The cap and lamp assembly and lamp housing 47, 48 and 49 are inserted upside down such that access is provided to the cap assembly from the top of the panel. In order that suitable connections may be made by the laterally extending leads illustrated at 50 and 51 to the power conductors 44 and 45 without modifying the basic panel structure, the leads are bent downwardly as indicated and then laterally.

The assembly is completed by an opaque annular gasket 52 which surrounds the cap structure 47 and extends partially within the bore 41 to block any light that may tend to leak upwardly about the edges of the cap 47.

While the structure of FIGURE 5 does have the slight disadvantage that the leads when bent as shown will eclipse part of the light radiating omni-directionally in the plane of the panel, the convenience of providing access from the front of the panel so that a lamp assembly may be replaced without having to remove the panel to gain access to the rear in many applications overcomes the slight diminution in the illumination as a consequence of the leads 50 and 51 cutting across the light path on opposite sides of the lamp housing.

From the foregoing description, it will be evident that the present invention has provided a greatly improved miniature light structure as well as an improved combination miniature light structure and edge lighted panel wherein all of the various objects and advantages described heretofore are fully realized.

Various changes that fall within the scope and spirit of this invention will occur to those skilled in the art. Thus, it is clear that the miniature light assembly structure itself will have application in other panels in addition to edge lighted panels. For example, they may easily and conveniently be employed in enunciator panel systems or as indicator lights per se. All of the various advantages of being able to replace the bulb itself without having to disturb the permanent connections to the filter assembly are realized.

The invention accordingly is not to be thought of as limited to the specific embodiments and application set forth merely for illustrative purposes.

What is claimed is:

1. A miniature light structure comprising, in combination, a filter assembly including: a lamp housing of light conducting material incorporating a threaded base ring in. a lower portion to define a lower opening into said lamp housing; first electrical lead means electrically joined to said base ring and extending from said housing; and second electrical lead means having a central contact portion disposed in said opening and a lead portion extending from said housing; and a cap and lamp assembly including: a threaded cap of electrically conducting material .adapted to be threaded into said base ring; a lamp having a lower portion centrally positioned in said cap and an upper portion dimensioned to be received through said lower opening and positioned in said lamp housing; a first input wire and a second input wire extending from said lower portion of said lamp; a collar member of conducting material surrounding the lower portion of said lamp, said first input wire connecting to said cap and said second input wire connecting to said collar member; and

insulating material holding said cap and collar in fixed, spaced, insulated relationship to each other to define said cap and lamp assembly such that said filter assembly may be permanently positioned inside a given structure with its electrical lead means permanently connected to a source of energy and its lower opening flush with a surface of said structure, and said cap and lamp assembly may be threaded as a unit into said lower opening to position the upper portion of said lamp in said lamp housing and effect electrical engagement between said central contact portions and said collar member, whereby said cap and lamp assembly may be readily replaced without disturbing said filter assembly and power connections thereto.

2. A miniature light structure according to claim 1, in which said central contact portion is flexed downwardly to engage said collar member prior to complete threading of said cap ring with said base ring whereby said contact portion is urged upwardly upon complete threading and thereby continuously exerts a bias force downwardly against said collar member to assure continuous electrical engagement with said collar member.

3. A miniature light structure according to claim 2, in which said central contact portion is defined by a ring of conducting material of diameter corresponding to the diameter of said collar member and coaxial with the axis of said collar member upon complete threading of said cap with said base ring.

4. A miniature light structure according to claim 1, including a metallic member defining part of the upper end portion of said lamp housing to provide a heat sink and block light from passing directly upwardly from said housing.

5. A miniature light structure according to claim 1, for use in combination with a panel, said panel comprising: a light conducting core in the form of a fiat sheet having at least one bore extending normally into said sheet from its bottom surface and dimensioned to receive said filter assembly; at least two conductor channels formed in the bottom surface of said core and running along said surface to pass adjacent to opposite sides of said bore, said sides of said bore including lead channels extending laterally to intercept, respectively, said conductor channels and being positioned and dimensioned to receive at least portions of said first and second electrical lead means, respectively, upon positioning of said filter assembly in said bore, whereby said lead means may be electrically connected to power carrying conductors disposed within said conductor channels at the point of interception of said lead channels with said conductor channels.

6. The subject matter of claim 5, in which said panel is counter-bored from its top surface at a point to intercept said bore, whereby said filter assembly may be positioned in said bore with its lower opening facing upwardly and said cap and lamp assembly threaded into said filter assembly from the top of said panel; and a light blocking gasket receivable in said counter-bore to surround said cap and block any light from passing about the edges of said cap.

7. A miniature light structure according to claim 1, in which said given structure comprises a panel, said panel including a light conducting core and top and bottom surfaces and at least one bore for receiving said filter assembly; and channel means formed in the bottom surface communicating with said bore, said source of energy being provided on power carrying conductor means in said channel means whereby said electrical lead means of said filter assembly may be electrically connected to said power carrying conductor means in said channel means.

8. A miniature light structure according to claim 7, in which the top surface of said panel has indicia markings thereon, said surface of said structure with which said lower opening of said filter assembly is flush constituting the bottom surface of said panel 50 that said cap and lamp assembly may be replaced from the bottom of said panel and said electrical lead means may be electrically connected to said power carrying conductor means in said channel means without eclipsing any light passing from said lamp housing omnidirectionally in the plane of said core when said lamp assembly is inserted in said housing.

9. A miniature light structure according to claim 7, in which the top surface of said panel has indicia markings thereon, said surface of said structure with which said lower opening of said filter assembly is flush constituting the top surface of said panel so that said cap and lamp assembly may be replaced from the top of said panel.

References Cited UNITED STATES PATENTS 2,696,550 12/1954 Neugass 240-2.1 3,065,335 11/1962 Madansky 2401 3,077,535 2/ 1963 Dupree.

NORTON ANSHER, Primary Examiner.

DAVID B. WEBSTER, Assistant Examiner.

US. Cl. X.R. 240-1 

